Weaving loom provided with a device for positioning a weft cutter thereon

Abstract: Weaving loom provided with a device for positioning at least one weft cutter relative to a sley in a specific direction, having a holder (1) and a bearing piece (30), which holder (1) is slidable in said bearing piece (30) wherein a multiple-rod system is provided for adjusting the slide of the sley, the multiple-rod system being coupled at its one end to the frame (17) by means of coupling elements, and being coupled at its other end to the slidable holder (1), and a hinged connection also being provided between said two ends of the multiple-rod system, said connection pivoting about a coupling shaft (4) which is supported on bearings in said at least one sley leg (5).

Description: This invention relates to a weaving loom provided with a device for positioning at least one weft cutter relative to a sley. Known weaving looms are provided with a sley which, as is known, carries out an oscillating movement along a path describing a circular arc. When a weft cutter is fixed directly on the sley of the weaving loom, said weft cutter describes the same path as the sley itself, in other words also in a circular arc. This means that when the sley reaches the open position, the tips of the weft cutters fixed directly thereon then lie just below the grippers, for presentation of the severed weft to the grippers. Document US-4875507 gives a good background as to dubbel weft cutters moving together with the sley and which in the beating-up position reach a position which is higher than the level of the woven fabric edges. Moreover, during the next beating-up movement, in the beating-up position of the reed, the weft cutter moves into a position which is much too high relative to the weft. The disadvantage of this is that the weft cutter is no longer capable of intercepting and severing the weft during said movement. The above can be overcome by providing additional guide elements such as guide plates, said guide elements lifting up the weft together with the weft cutter. However, the disadvantage of this is that it leads to breakdowns, caused by the weft thread becoming stuck. Another disadvantage of this is that it results in the production of longer weft loss ends in the woven fabric, and thus to material loss, and in some cases an increasing risk of manufacturing faults in the woven fabric. In document EP-0104440, there is shown how the weft threads are pushed up by guide plates so as to be intercepted by the weft cutters standing higher on the sley. In FR-A-1571926 there is recited a weaving loom provided with a device for positioning at least one weft cutter relative to the sley having a holder for carrying said weft cutter and a bearing piece for accommodating the holder. The object of the invention is to provide a solution to the abovementioned problems. To this end, there is provided according to the invention a weaving loom as defined in Claim 1 whereby the holder is slidably mounted inside the bearing piece so that it slides in a specific direction, thereby allowing the weft cutter to carry out an upward and downward movement. According to an advantageous embodiment of the invention, the bearing piece comprises a body and a tubular guide element connected immovably thereto, said body forming the part which is fixed immovably to the sley. The holder comprises a further body and a projection part which is connected immovably thereto and is provided for sliding inside said guide element, the sliding direction being at right angles to the lengthwise direction of the sley. According to a further embodiment of the invention, a multiple-rod system is provided for adjusting the slide of the holder in the bearing piece while driving the movement of the sley. The multiple-rod system is coupled at its one end to a frame by means of further coupling elements, and is coupled at its other end to the slidable holder. A hinged connection is also provided between said two ends of the multiple-rod system, said connection pivoting about a coupling shaft which is supported on bearings in said at least one sley leg. Each weft cutter is thus expediently mounted on the holder, and the holder is slidable in the bearing piece. The bearing piece is fixed immovably on the sley in such a way that each weft cutter can carry out a to and fro movement in a specific direction. This to and fro movement is caused by the multiple-rod mechanism, which is driven by means of the sley movement by way of coupling elements. Said multiple-rod mechanism forms a balancing lever which is mounted on bearings in the reed lever. One side of the balancing lever is immovably connected to the frame of the weaving loom by means of a drive rod, and the other side of the balancing lever is coupled by means of a further drive rod to the slidable holder. In the case of weaving looms, the loom reed undergoes a movement in which the reed alternately assumes a higher vertical position, on the one hand, and a lower vertical position, on the other hand. When a multiple-rod mechanism is provided, it is desirable in this case for the fell of the woven fabric ultimately to lie as close as possible to the reed, in order to keep the bending moment on the reed dents and on the reed as low as possible. For this purpose, the multiple-rod side of the reed movement is designed in such a way that the reed reaches its highest position in its so-called front, beating-up position and assumes a lower position in its so-called open, rear position. This ensures that warp threads form a downward oriented angle for the shed opening. According to a particularly advantageous embodiment of the invention, said multiple-rod system consists of a four-rod mechanism containing a double pair, each pair having a connecting point in said coupling shaft, in which a respective lever engages and forms the connection with a respective drive rod, which drive rods in each case engage in said two ends of the four-rod system. More particularly, said slidable holder and the bearing piece form a slide pair, and said bearing piece has a certain inclination or can also possibly be arranged substantially vertically. The slide pair is advantageously inclined in such a way that each weft cutter also has a front and rear component, resulting in that both a vertical and a horizontal positioning of said at least one weft cutter can be obtained. According to a further particular embodiment of the invention, the slide pair is disposed substantially vertically. This means that each weft cutter can carry out a substantially vertical up and down movement, resulting in that a height positioning of each weft cutter can be obtained. Some space can be gained through the vertical arrangement. Further advantages and particulars of the weaving loom according to the invention will emerge from the following description of an exemplary embodiment of the device with reference to appended drawings. Figure 1 is a schematic diagram of a positioning device with a loom reed according to the invention. Figure 2 shows a partial cross-section of the positioning device according to the invention, in the highest position or equilibrium position of the loom reed. Figure 3 is a diagram similar to that shown in Figure 2, in a lower or deflected position of the reed. Figure 1 shows a general perspective view of the part of a weaving loom in which a positioning device of two weft cutters 11, 12 according to the invention is accommodated. The weaving loom is provided with a sley 9, which carries out an alternating circular movement through a given angle α between a first, highest position A, as shown in Figure 2, and a second, open position B, as shown in Figure 3. The sley is moved by being driven by drive elements 100. The sley in this case has a set of elongated sley legs 5, which are disposed at a certain distance from each other and serve as coupling elements between the sley and the sley shaft 110 disposed parallel thereto. The sley shaft is supported in bearing blocks 111 on the frame 107 of the weaving loom and acts as a rotary shaft for the sley by way of the sley legs 5. Each sley leg 5 is in this case rotatably connected at its one end to the sley shaft and at its other end to the sley itself by means of a coupling piece 120 by way of a coupling shaft 105. In this case said one end of each sley leg 5 is advantageously interrupted in such a way that said one end consists of two arms turned towards each other, in which the tension relative to the sley shaft can be regulated in a suitable manner by means of a tensioning nut 121. The coupling piece 120 is a part of said drive element 100 which is subjected to a movement under the influence of a rotary drive rod, to which it is rotatably connected by means of a shaft 112 supported on bearings therein. The coupling piece 120 has on its sley side a projecting profile which is suitably provided in a longitudinally profiled recess 130 on the underside of the sley. Each sley leg 5 is driven individually by one corresponding drive element 100, as can be seen from Figure 1. Two weft cutters 11, 12 are also immovably mounted together on a holder 1. According to the invention, the holder 1 is slidably disposed in a bearing piece 30, which in turn is fixed laterally to the sley 9. More particularly, the bearing piece 30 consists of an element 31 fixed to the sley 9 and a guide element 32, e.g. tubular, which is immovably connected to the element 31. The holder 1 comprises a bearing plate 18, which serves as a support for the two weft cutters 11, 12, and a projecting part 19 opposite it which is provided for sliding into said tubular guide element of the bearing piece 30, in particular in a direction which is crosswise to the lengthwise direction of the sley 9, which is indicated by arrow F in the figures. The result of this is that the two weft cutters 11, 12 can make a to and fro movement relative to the sley in a particular direction. In a virtually vertical arrangement of the slide pair, consisting of the slidable holder 1 and the bearing piece 30, said to and fro movement of the two weft cutters 11, 12 is virtually vertical, in such a way that a height positioning of the weft cutters is thereby achieved. However, in a variant said slide pair 1, 30 can advantageously be given a certain angle of inclination, in such a way that herewith the weft cutters 11, 12 also have a forward and backward movement component. This embodiment ensures that there can be both vertical and horizontal positioning of the weft cutters 11, 12 relative to the sley. In order to produce said to and fro movement of the weft cutters 11, 12 in a particularly expedient way, a multiple-rod system is provided according to the invention. The drive of the rod mechanism is produced by the movement of the sley itself. Said multiple-rod system according to the invention consists of a balancing lever which is supported on bearings in the reed lever or sley leg 5 by means of a shaft 4. One side of the balancing lever is rotatably coupled to the frame by means of a first drive rod 7, which is immovably connected to a shaft 8 at its one end. The shaft 8 is supported in bearing blocks 16 on the frame 17. At its other end said first drive rod 7 is connected to a lever 6, which is connected directly to the shaft 4. A further lever 3 is also fixed at one end to said shaft 4 and is connected at the opposite end to a second drive rod 2 by way of an intermediate shaft 23. The other side of the balance is thus coupled to the slidable holder 1 by way of said second drive rod 2. This means that the slidable holder 1 can be held in a certain position relative to the sley by said second drive rod 2. A to and fro rotary movement of the reed lever 5 about the shaft 110 consequently produces the necessary up and down movement of the weft cutters 11, 12. The inclination of the slide pair 1, 30 can also be selected in such a way that the weft cutters 11, 12 slide backwards relative to the loom reed in the beating-up position and slide forwards relative to the reed in the open position, so that the tips of the weft cutter can pass the weft 50 better to the gripper and in front of the reed block. The abovementioned multiple-rod system can also be driven by means of a cam element 60, which is provided on the frame, and said cam element in this case is rotatably connected to the frame.

Claims: Weaving loom provided with a device for positioning at least one weft cutter relative to a sley of a weaving loom in a specific direction, having a holder (1) for carrying said at least one weft cutter (11, 12) and a bearing piece (30) for accommodating the holder (1), which bearing piece is fixed immovably on the sley, which has at least one sley leg (5), a first end of which is rotatably connected to the sley by means of coupling elements, characterised in that the holder (1) is slidably mounted inside the bearing piece (30) so that it slides in a specific direction (F). Weaving loom according to Claim 1, characterised in that the bearing piece (30) comprises a body (31) and a tubular guide element (32) connected immovably thereto, said body forming the part which is fixed immovably to the sley, and in that the holder (1) comprises a further body (18) and a projecting part (19) which is connected immovably thereto and is provided for sliding inside said guide element (32), the sliding direction (F) being at right angles to the lengthwise direction of the sley (9). Weaving loom according to one of Claims 1 or 2, characterised in that a multiple-rod system is provided for adjusting the slide of the holder (1) in the bearing piece (30) while driving the movement of the sley, the multiple-rod system being coupled at its one end to a frame (17) by means of further coupling elements, and being coupled at its other end to the slidable holder (1), and a hinged connection also being provided between said two ends of the multiple-rod system, said connection pivoting about a coupling shaft (4) which is supported on bearings in said at least one sley leg (5). Weaving loom according to Claim 3, characterised in that said multiple-rod system consists of a four-rod mechanism containing a double pair (2, 3; 6, 7), each pair (2,3) and (6,7) respectively having a connecting point in said coupling shaft (4), in which a respective lever (3; 6) engages and forms the connection with a respective drive rod (2; 7), which drive rods respectively engage in said two ends of the multiple-rod system. Weaving loom according to one of Claims 1 to 4, characterised in that said holder (1) and said bearing piece (30) form a slide pair, and in that said bearing piece (30) has a certain inclination. Weaving loom according to one of Claims 1 to 4, characterised in that said holder (1) and said bearing piece (30) form a slide pair, and in that said bearing piece (30) is disposed substantially vertically. Weaving loom according to one of Claims 3 to 5, characterised in that a cam element (60) is provided on the frame (17), for driving said multiple-rod system, said cam element (60) being rotatably connected to the frame (17). Positioning device for at least one weft cutter relative to a sley of a weaving loom in a specific direction, having a holder (1) for carrying said at least one weft cutter (11, 12) and a bearing piece (30) for accommodating the holder (1), which bearing piece is fixed immovably on the sley, which has at least one sley leg (5), a first end of which is rotatably connected to the sley by means of coupling elements, characterised in that the holder (1) is slidable in the bearing piece (30) and in that a multiple-rod system is provided for adjusting the slide of the holder (1) in the bearing piece (30) while driving the movement of the sley, the multiple-rod system being coupled at its one end to a frame (17) by means of coupling elements, and being coupled at its other end to the slidable holder (1), and a hinged connection also being provided between said two ends of the multiple-rod system, said connection pivoting about a coupling shaft (4) which is supported on bearings in said at least one sley leg (5).

Inventors: DEBAES JOHNNY, DEJAEGERE FERDI, DEBAES, JOHNNY, DEJAEGERE, FERDI
Applicants: WIELE MICHEL VAN DE NV, N.V. MICHEL VAN DE WIELE
Application year: 1994
Main classification: D03D47
IPC codes: D03D49, D03D47